Today again someone took it upon themselves to send out router
advertisements even though they're not a legitimate IPv6 router, with
broken IPv6 connectivity as a result.
On the Mac, where IPv6 is enabled by default, so apparent but non-
working IPv6 connectivity is extremely annoying, you can see this with:
ndp -an
Neighbor Linklayer Address Netif Expire St
Flgs Prbs
::1 (incomplete) lo0 permanent R
[...]
fe80::204:23ff:fe50:c11d%en0 0:4:23:50:c1:1d en0 23h48m39s S R
fe80::206:d6ff:fe0f:b806%en0 0:6:d6:f:b8:6 en0 23h59m42s S R
fe80::20a:95ff:fecd:987a%en0 0:a:95:cd:98:7a en0 permanent R
fe80::212:f0ff:fe5f:c4ec%en0 0:12:f0:5f:c4:ec en0 23h52m15s S R
An R "flg" indicates a router, with fe80::206:d6ff:fe0f:b806 being
the real one.
You can filter out the unwanted router advertisements with:
sudo ip6fw add 10 permit ipv6-icmp from fe80::206:d6ff:fe0f:b806 to
any icmptypes 134 in
sudo ip6fw add 20 drop ipv6-icmp from any to any icmptypes 134 in
And if you already have broken connectivity, filtering all ICMP
messages towards the "router" in question will kickstart dead
neighbor detection:
sudo ip6fw add 30 drop ipv6-icmp from fe80::204:23ff:fe50:c11d to any
Shortly after this you can enjoy the fabulous IPv6 connectivity that
the IETF66 meeting has to offer:
traceroute6 to www.ietf.org (2001:503:c779:b::d1ad:35b4) from
2001:510:102:100:20a:95ff:fecd:987a, 30 hops max, 12 byte packets
1 2001:510:102:100:206:d6ff:fe0f:b806 7.125 ms 0.668 ms 0.561 ms
2 2001:510:100:100::84ca:1c8 0.765 ms !N 0.944 ms !N 3.284 ms !N
traceroute6 to www.isc.org (2001:4f8:0:2::d) from
2001:510:102:100:20a:95ff:fecd:987a, 30 hops max, 12 byte packets
1 2001:510:102:100:206:d6ff:fe0f:b806 2.201 ms 7.626 ms 1.444 ms
2 2001:410:101:13::1 1.846 ms 1.736 ms 3.85 ms
3 2001:410:101:5::1 24.331 ms 24.983 ms 102.792 ms
4 2001:410:101:30::2 239.214 ms 96.351 ms 96.318 ms
5 2001:320:1b00:1::1 210.57 ms 210.528 ms 210.714 ms
6 2001:320:1a05::10 211.26 ms 220.1 ms 210.472 ms
7 2001:320:1a05::20 211.47 ms 254.317 ms 211.431 ms
8 2001:320:1a09::1 214.655 ms 214.478 ms 214.43 ms
9 2001:320:1a07::2 216.013 ms 216.143 ms 215.784 ms
10 2001:2b8:5:10::2 214.027 ms 228.96 ms 214.316 ms
11 2001:220:1000:42e::2 214.341 ms 220.359 ms 214.777 ms
12 2001:220:1000:400::1 217.728 ms 217.345 ms 217.12 ms
13 2001:220:400:200::1 219.455 ms 266.643 ms 219.859 ms
14 2001:220:1800:200::1 220.861 ms 223.042 ms 391.591 ms
15 3ffe:8140:101:1a::162 228.454 ms 228.31 ms 227.647 ms
16 2001:200:901:1036::2 266.8 ms 228.512 ms 239.632 ms
17 2001:200:901:7::18 228.109 ms 228.281 ms 228.358 ms
18 as2914.nspixp6.net.wide.ad.jp 289.724 ms 288.772 ms 288.343 ms
19 ge-7-0-0.a20.tokyjp01.jp.ra.gin.ntt.net 288.219 ms 288.992 ms
292.174 ms
20 xe-0-0-0.r20.tokyjp01.jp.bb.gin.ntt.net 287.444 ms 289.068 ms
287.622 ms
21 p64-2-3-0.r21.mlpsca01.us.bb.gin.ntt.net 308.109 ms 305.339 ms
304.836 ms
22 xe-0-2-0.r21.plalca01.us.bb.gin.ntt.net 425.596 ms
p64-0-0-0.r21.plalca01.us.bb.gin.ntt.net 319.325 ms 304.013 ms
23 p16-1-0-0.r00.plalca01.us.bb.gin.ntt.net 304.464 ms 338.699 ms
305.647 ms
24 p1-0.isc.plalca01.us.bb.gin.ntt.net 318.962 ms 306.91 ms
303.59 ms
25 www.isc.org 306.776 ms 305.18 ms 304.959 ms
IPv4:
traceroute to www.isc.org (204.152.184.88), 64 hops max, 40 byte packets
1 h0003-net84db (132.219.0.3) 1.761 ms 0.492 ms 0.352 ms
2 ericsson1-internet.dmtrl-uq.risq.net (132.202.60.65) 0.473 ms
0.515 ms 0.416 ms
3 amtrl-rq.risq.net (192.77.63.49) 0.418 ms 0.475 ms 0.438 ms
4 192.77.63.37 (192.77.63.37) 0.417 ms 0.542 ms 0.411 ms
5 vlan254.msfc2.mtt-montreal.teleglobe.net (66.198.80.1) 0.607 ms
0.647 ms 1.661 ms
6 if-10-0.core1.mtt-montreal.teleglobe.net (207.45.221.129) 1.189
ms 0.594 ms 0.587 ms
7 if-1-3.mcore4.nqt-newyork.teleglobe.net (66.198.81.14) 82.572 ms
82.549 ms 82.575 ms
8 if-4-0.mcore4.pdi-paloalto.teleglobe.net (216.6.86.13) 105.497
ms 83.140 ms 82.882 ms
9 if-7-0.core3.pdi-paloalto.teleglobe.net (216.6.86.2) 82.927 ms
82.929 ms 82.809 ms
10 ix-4-6.core3.pdi-paloalto.teleglobe.net (207.45.196.66) 83.162
ms 82.964 ms 83.226 ms
11 external.isc.org (204.152.184.88) 92.539 ms 82.764 ms 82.776 ms
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